/Engine/Plugins/Animation/ControlRig/Source/ControlRig/Public/Rigs/RigHierarchy.h
Unsets a curve's value. Basically the curve's value becomes meaningless.
void UnsetCurveValue ( [FRigCurveElement](API\Plugins\ControlRig\Rigs\FRigCurveElement) * InCurveElement, bool bSetupUndo, bool bForce )